As is well-known, for example, in an imaging device such as a digital still camera or a digital video camera, an optical image of an imaged object is converted into an electric video signal by focusing the optical image on an imaging element. The video signal is subjected to various kinds of signal processing, and is then output externally or recorded on a recording medium.
In this case, a level range of a video signal which is output from the imaging device is defined to be narrower than a level range of a video signal obtained from an imaging element, according to standards. Therefore, the imaging device is configured to perform a knee correction processing by which high luminance components of a video signal obtained from the imaging element are subjected to level compression in order to set the level range of the output video signal within a standard.
Meanwhile, a knee correction processing technique as described above is still under development, and there still remain various points to be improved for practical use. For example, when a chromatic color is imaged according to a conventional knee correction processing technique, hue of high luminance components of a video signal is not correctly reproduced by a level compression processing but causes hue rotation, as is known.